The overall goal of the proposed research is to investigate brain mechanisms underlying normal human perception, cognition, and action; the approach will be study patterns of sparing and loss of function in patients with selected cerebral lesions. This inquiry, grounded both in neuroscience and in cognitive science, relates the specific deficits that follow brain injury to theories of brain organization and to the interplay of cognitive systems. The aspects of behavior that we have selected include memory, cognitive functions other than memory, and sensory and sensorimotor capacities ranging from simple to complex. Two groups of subjects will be studied: men with cerebral injuries sustained during World War II or the Korean Camgaign; and men and women with amnesias of several different etiolgies, resulting from damage to various discrete brain structures. Control subjects will include World War II veterans with peripheral nerve injuries, healthy Korean Campaign veterans, and normal civilian subjects. All of the veterans previously participated in neuropsychological studies in our laboratory or its predecessor, H.-L. Teuber's laboratory at Bellevue Hospital in New York. The proposed work represents 15-year to 40-year follow up studies in these men. The amnesic patients, many of whom have already been identified, are referred regularly by our consultants at local hospitals. All veterans, amnesic patients, and control subjects will be admitted to the MIT Clinical Research Center for extensive neuropsychological examination.